On 10 January 2012 20:07, John Harper wrote: > > My little test program then compiled but wouldn't run even though the > library said to be missing does exist. It was presumably put somewhere > > that gfortran couldn't find it. What should I do now? Evidence: [...] > ./a.out: error while loading shared libraries: libquadmath.so.0: cannot open > shared object file: No such file or directory In my reply directing you to the gcc-help list I also answered your question, I guess you didn't scroll down far enough :) I said: The dynamic linker needs to know how to find the library at run time. http://gcc.gnu.org/onlinedocs/libstdc++/faq.html#faq.how_to_set_paths